The CHUM's primary mission is to provide inpatient and ambulatory care to its immediate urban clientele and specialized and ultraspecialized services to the broader metropolitan and provincial population.

Prior to the concentration of services at the megahospital site, the three campuses formed interdependent components of the CHUM network; together, they hosted 1,259 beds and employ 330 managers, 881 physicians, 1,300 researchers and educators, 1,458 technicians, and 4,273 nurses.

[2] The long and troubled history of the CHUM superhospital began in 1999, when then-health minister Pauline Marois announced that the megaproject would go ahead for a price tag of 700 million dollars and be built at 6000, Saint Denis Street, the site of a major bus depot.

[3] In 2003, the incoming Liberal government of Jean Charest questioned this decision and launched a commission presided by Daniel Johnson and Brian Mulroney to study other sites.

That same year however, many prominent Québécois, led by Université de Montréal rector Robert Lacroix and former Premier Lucien Bouchard, publicly pushed for the hospital to be built on the site of the Outremont rail yard, leading to a media controversy and new delays.

[5] Laing O'Rourke, in a joint venture with Spain's Obrascón Huarte Lain, is delivering the project as a public-private partnership (PPP).

Pavillon Edouard Asselin at 264 Rene-Levesque East Boulevard, built in 1959 and formerly part of the now-defunct Hôpital Saint-Luc, is also a component of the megahospital.

Located on Saint Urbain Street near downtown Montreal, it functioned as a full service teaching hospital and maintained an emergency department with level II trauma care capabilities.